Biomedical subjects

David S Blondheim

Publications and source records attributed to David S Blondheim.

5 recordsLinked to original sources

PubMed2005

Relation of left atrial size to function as determined by transesophageal echocardiography.

One hundred thirty-nine patients who underwent transesophageal echocardiographic studies were grouped by their maximal left atrial (LA) volumes, and their stroke volumes, emptying fractions, and fractional shortening were calculated. In large atria, an inverse relation was found between further increases in LA volume and LA function, determined by emptying fractions and fractional shortening.

Atrial Function, Left↗

PubMed2005

Fluid overload contributing to heart failure.

BACKGROUND: In advanced heart failure, the compensatory responses to reduced cardiac output, in spite of fluid retention, lead to maladaptive consequences. METHODS: We performed a Medline survey for fluid overload and heart failure as well as reviewing textbook chapters. RESULTS: The increased sympathetic nervous system, renin-angiotensin-aldosterone system, and antidiuretic hormone stimulation and release lead to a vicious cycle--augmenting pre-load, contractility and after-load, as well as increased fluid overload. The elevated work load on an already failed cardio-circulatory system results in further deterioration. Plasma volume is usually increased in untreated patients with increased extracellular fluid. However, it may range from reduced to increased in treated patients. Currently, diuretics remain the initial first line of therapy. In refractory cases, restoring plasma volume and osmolality, by adding albumin or hypertonic saline solutions, neurohormonal antagonists such as vasopressin receptors antagonists, aldosterone antagonists, or administration of nesiritide, may help in overcoming fluid overload. CONCLUSION: Exact measurement of plasma volume in various forms of heart failure and adjusting the treatment accordingly, establishing favourable and detrimental effects of various therapies, and introducing additional and new therapeutic options require further investigation.

Cardiac Output↗

PubMed2005

Efficacy and safety of contrast injection beyond total occlusions in acute cardiac patients: a method to confirm balloon position within coronary lumen.

OBJECTIVES: To evaluate the sensitivity and safety of contrast injection beyond total occlusions in acute cardiac patients in order to ensure balloon position within the coronary lumen and occasionally to enable the estimate of occlusion length. BACKGROUND: Percutaneous therapy of total coronary occlusions is generally more challenging than the treatment of stenotic lesions. It more frequently entails the risk of irreversibly disrupting a protruding plaque, of advancing the wire through a false route, or rarely, of causing coronary perforation. Therefore, ascertaining intraluminal position prior to inflation is important. METHODS: In a large group of consecutive acute cardiac patients undergoing percutaneous coronary intervention (PCI) we employed a technique of crossing the lesion with a soft-tipped guidewire supported by an over-the-wire (OTW) balloon catheter, and then injecting dilute contrast through the balloon under fluoroscopy to achieve distal lumen visualization. RESULTS: In 106 patients, this technique yielded a sensitivity of 94%, a specificity of 70%, a positive predictive accuracy of 97%, and a negative predictive accuracy of 54% for intraluminal position of the balloon. CONCLUSIONS: The technique of lumen demonstration by contrast injection through an OTW balloon beyond acute or subacute total obstructions was shown to be a safe and effective method to ascertain proper position of the angioplasty balloon. Occasionally, it enabled the estimation of lesion length or the identification of lesions distal to the obstruction. This technique was found to be valuable in doubtful situations where the determination of wire position was crucial for achieving procedural success.

Acute Disease↗

PubMed2004

Effect of nutritional composition of meals on exercise tests in patients with ischaemic heart disease.

BACKGROUND: Patients with ischaemic heart disease have to perform exercise tests repeatedly. It is not clear if a small meal eaten before the test might influence it and if the meal's composition is important. DESIGN AND METHOD: We performed a double blind, randomised, crossover study on 20 volunteers with documented ischaemic heart disease known to have positive exercise tests. Each had three symptom limited exercise tests done one hour after a 200 ml meal, rich in either fat, carbohydrate or protein. Each postprandial test was compared to a fasting exercise test performed just before the meal. RESULTS: Postprandial blood pressure, time to angina and to peak exercise and double product at onset of ST-depression were not significantly altered by any of the meals. Heart rate was slightly increased only after the fat meal. CONCLUSIONS: The nutritional composition of a small meal eaten an hour before an exercise test has no clinically important impact on the results of the test in patients with stable angina pectoris.

Aged↗

PubMed2004

Mild sedation before transesophageal echo induces significant hemodynamic and respiratory depression.

AIMS: Midazolam is often used for conscious sedation before transesophageal echo (TEE) studies. It is not clear to what extent midazolam administration or the insertion of the TEE probe itself is responsible for the respiratory and hemodynamic depression during TEE examinations. We compared the performance of TEE with versus without midazolam to elucidate the effects of each. METHODS: Patients were given the choice of having midazolam prior to their TEE. Thirty-one patients preferred to have sedation (Sed+) and 31 others declined sedation (Sed-). Both groups had SaO(2) and blood pressure measured before the study, following sedation (in Sed+) and at the end of the TEE study. RESULTS: Increase in HR was greater in Sed+ than in Sed- (12 +/- 19% vs 6 +/- 11%, both P < 0.05). There was a greater decrease in saturation of O(2) in Sed+ than in Sed- (3 +/- 3% vs 2 +/- 3%, both P < 0.05). Systolic blood pressure (SBP) increased in Sed- by 6 +/- 11% (P< 0.05) but dropped in Sed+ immediately after sedation (16 +/- 8%, P < 0.000001). Diastolic blood pressure decreased in Sed+ after sedation by 11 +/- 9% (P < 0.05). CONCLUSIONS: Midazolam sedation before TEE examinations causes more prominent tachycardia and depression of SaO(2)than insertion of the TEE probe alone. It also causes a substantial drop in SBP. Midazolam should be offered only to hemodynamically stable patients without preceding respiratory depression.

Aged↗